1. Field of the Invention
The present invention relates to robotic devices. More particularly, the present invention relates to a pressure transmission assembly for mounting to a robotic device having a rotatable end effector.
2. Description of the Prior Art and Related Information
Robotic devices having jointed-arms may be utilized to perform complex actions by the various sections of the robot arm pivoting and rotating around various joints or axes. Further, a wrist is typically attached to the robot arm. The wrist may often pivot or rotate along two axes.
Attached to the wrist may be one or more end effectors that need to be supplied with energy, pressure, medium, coolant, etc., to perform their various functions. This supply may take place via a plurality of connections, which may be formed as electric cables, hoses, pressure tubes, or the like. The end effectors typically require the supply during all the movements of the end effector for long periods of time.
The movements of the robotic device including the end effectors, may be programmed into a microprocessor and directed in a predetermined or desired path or pattern so that various tasks may be accomplished. A jointed-arm robot can accomplish a variety of different tasks by utilizng different end effectors such as grippers, welders, vacuum heads, or other devices mounted on its wrist. Each end effector has certain power, sensing, communication, and pneumatic, fluid, or gas requirements. For example, an end effector may be designed to lift and move objects by means of a vacuum or a gripper. It should be appreciated that various types of end effectors may require a source of electric power, pneumatic power, and/or hydraulic power in order to drive and move the various components of the end effector.
Accordingly, most modern robots require a means for supplying or transmitting pressure to the end effector, such as hydraulic or pneumatic pressure. With respect to the supply sources, they are generally sourced far away from the end effector and must be routed to the end effector. The general practice in robot design is to design a robot for a specific application with a certain range of motion and then arrange and mount any required supply lines from a supply point down to the end effectors.
Unfortunately, for robots having end effectors mounted to a rotatable wrist that require a pressure supply (e.g. pneumatic or hydraulic), the pressure supply source is generally located a relatively long distance away from the end effector. Typically, the pressure supply connection to the end effector is drawn from a fixed external point in a service tube loop configuration that is arranged to run and loop down to the end effector. These service tube loops ensure that the bundle of tubes may follow all the movements of the end effector.
However, the service tube loops are subjected to a great number of bendings in various directions and with different radii of bending. This constant bending and movement often causes the breaking or pinching of tubes and particle generation. Further, these service tube loops often drag or catch on other tooling. This sort of arrangement often results in the need to repair broken tubes and take the robot off-line. Moreover, this sort of arrangement is unsuitable for a clean-room environment.
There is therefore a need for an effective means to deliver pressure signals down to the rotatable end effectors of a robot in a more compact and less burdensome fashion.